The present invention relates to improvements in a trailer bumper hitch; and more particularly, the improvements relate to the hitch disclosed in the Antici U.S. Pat. No. 3,140,881, issued July 14, 1964. This patent discloses a trailer hitch which makes it easier to attach the draw bar to the trailer by two release mechanisms. One of these release mechanisms permits the draw bar to be moved longitudinally toward the rear when the release is actuated so that it can be aligned with the hitch of the trailer, and the other release mechanism permits the draw bar to be swung laterally in any rearwardly extended position--thus greatly increasing the range over which the draw bar can be connected to the trailer without further moving either vehicle. This trailer hitch has the further advantage that no special maneuvering is required to reset both release mechanisms. When the towing vehicle turns, the lateral release mechanism is reset, and when the towing vehicle brakes or slows down, the longitudinal release mechanism is reset. Further, both releases and reset mechanisms operate independently of each other. This trailer hitch has provided substantial convenience to users, particularly in the agricultural industry where trailer loads may be quite heavy, and the terrain at which it is desired to hitch a trailer to the towing vehicle may be rough or uneven.
Despite the substantial convenience of this bumper hitch and its commercial success, there are two relatively minor aspects in the commercial version of the hitch which proved to be slight inconveniences to the user. Even though they were slight, however, it must be realized that the primary purpose of the hitch is to provide convenience to the user. Hence, even slight inconveniences might have an impact in original or re-sale of a hitch.
The first inconvenience is the actuation of the longitudinal release mechanism for the draw bar. It included a pin which had to be aligned with a vertical aperture in the draw bar in the reset position. Although the original Antici patent disclosed in one embodiment an actuating lever for this release pin which was located beneath the floorboards of the truck on which the hitch is mounted and above the hitch itself, nevertheless, this proved to be impractical and was not incorporated into the commercial version. Rather, in the commercial version, the longitudinal release mechanism included a lever located beneath the hitch mechanism for withdrawing the longitudinal locking pin to permit the draw bar to be pulled to the rear. This arrangement had the disadvantage that because it was placed beneath the hitch, which itself is mounted beneath the bed of a vehicle such as a pick-up truck, it was possible to break or bend this handle or lever by passing over a log or stump or the like. Still further, it was somewhat inconvenient to reach and actuate.
Another disadvantage in the commercial version of the hitch is that even though the longitudinal release mechanism for the draw bar were actuated, it sometimes became difficult to pull the draw bar longitudinally to align it with the hitch of the trailer. The reason for this, it was found, after studying the problem, is that whereas the front and rear of the draw bar were supported, the entire spring assembly which cushioned the draft forces rests on the middle of the bar. Because this is a heavy duty structure, the weight of the spring assembly is as much as thirty pounds, and it is the binding action of the weight of the spring assembly which in some instances made it difficult to withdraw the draw bar even though the longitudinal release mechanism is actuated.
The present invention, then, is directed to improvements in overcoming the above operational problem, and in further providing advantages in manufacturing which effect production cost reductions.
According to the present invention a clevis-type of receptacle is formed integrally with the spring assembly mounting casting, and it is adapted to mount to a horizontal member of the hitch frame by means of a vertical threaded fastener such as a bolt which, when tightened, adjusts the elevation of the spring assembly by rotating it about the horizontal frame member. A shim effect is achieved by a slight off-parallel alignment of the clevis-type receptacle and the axes of the spring assembly. This permits the spring assembly to be elevated about the draw bar and makes it easier to telescope the draw bar when the spring assembly is thus cantilevered relative to the horizontal frame member and does not rest on the draw bar.
Further, the spring casting includes a pair of upper dogs for mounting an actuating lever between a latching and an unlatched position by moving the lever downwardly. The lever is located between the bed of the towing vehicle and the hitch spring assembly. A latch member is provided on top of the draw bar and it is locked between the spring casting and the lever to lock the draw bar longitudinally. The draw bar is released when the lever is lowered to permit the latch member to be extended beneath the lever toward the rear, for alignment with a trailer hitch.
To reduce manufacturing costs, the four springs included in the spring assembly for cushioning the draft forces are provided with conforming seating surfaces both in the spring assembly mounting casting and the spring center casting, as well as in the spring end clamp members. The ends of all four springs which are remote from the center casting are turned radially inwardly and clamped by means of the spacer tube to the outboard ends of the assembly, which spacer tubes are received within the springs.
Other features and advantages of the present invention will be apparent from the following detailed description of a preferred embodiment accompanied by the attached drawing wherein identical reference numerals will refer to like parts in the various views.